Large cranes, in particular large crawler-mounted cranes, require a considerable counter-weight which counteracts the raised payload and prevents the tilting of the crane. This counter-weight can be applied by a central ballast, by a superstructure ballast or also by a ballast at the derrick boom. As a rule, a ballast plate supported with respect to the ground via corresponding auxiliary means to take up the ballast is proposed as a possible derrick ballast. A completely suspended ballast or also a derrick ballast carried by a ballast box is possible as an alternative.
Against this background, special ballast boxes have been developed which are designed as independently driven vehicles and can therefore be moved together with the crane to ensure a largely unrestricted crane operation. Such solutions, however, always require a complex separate development of a suitable ballast box which is used only for the ballast application. Furthermore, such a ballast box has to be transported separately onto the construction site for the crane use, which has a disadvantageous effect on the deployment costs incurred since they depend as a rule on the required ballast mass.
DE 10 2011 105 960 A1 describes connecting an auxiliary crane having a telescopic boom as a derrick ballast to a crane. This ballast application possibility can be used, for example, during regular crane deployment or during the crane equipping process, especially during the erection process of the luffable boom system. A comparatively small crane required for the equipping procedure of the large crawler-mounted crane can be used as the auxiliary crane, for example.
It has furthermore has been proposed in the non-pre-published DE 10 2014 012 661 A1 to use an auxiliary crane as a ballast box having an additional added suspended ballast.
It must, however, be considered that a lattice crane with suspended ballast has to observe a plurality of failure criteria. It is thus clear that a tilting of the total crane to the rear beyond the tilting edge, that is beyond the end of the footprint on the ground, has to be prevented. This can take place via the monitoring of the overall center of gravity.
A further feature is the prevention of an uncontrolled pivoting of a boom element to the rear about its lulling axis. The main boom, e.g. the boom system, or the derrick boom, can be boom elements. Securities against fall-back admittedly counteract this effect, but their performance capability is limited. The crane statics must also be considered for the case of a “breaking away of the load”. The crane may not tilt to the rear in this case.
A further aspect for the design of the crane is a space requirement which is as small as possible on the construction site. A very large number of transportation trucks are thus in use on construction sites, in particular construction sites for assembling wind power stations. They have to move very close to the crane in order to keep the outreach of the crane small when taking up the loads. Some solutions have already been put forward for these problems. DE 296 07 257 U1 thus shows a crane having a gate-shaped undercarriage. A truck can drive through this gate-shaped undercarriage. DE 10 2007 028 778 A1 furthermore shows a crane having a connection between the superstructure and the ballast box which is disposed higher and likewise allows a driving through of a truck.
Finally, it has been proposed in EP 2 308 792 A1 for the prevention of a state in which the crane tilts to the rear or is pulled to the rear by the suspended ballast that a triangular derrick very greatly reduces the spacing in the direction of the longitudinal axis of the superstructure between the axis of the superstructure and the suspended ballast. A very high derrick ballast is attached in this solution in order thus to be able to reduce the derrick ballast radius.
The aforesaid solutions each have different advantages and disadvantages.
The solution in accordance with DE 10 2011 105 960 A1 thus has the advantage that a small crane present on the construction site can be used as derrick ballast so that no separate ballast box has to be kept available. On the other hand, the coupling mechanism of this auxiliary crane with the crane to have ballast attached is comparatively complex so that a complex use of the auxiliary crane is provided which has a large dismantling effort.
It is thus the object of the present disclosure to provide a method of operating a crane and a corresponding crane which provides the counter-ballast which is required for the different load states during the erection of the crane, on the one hand, but also allows operation of the crane fast and in a simple manner and with means which are as simple as possible.
This object may be achieved by a crane having a travelable undercarriage, a superstructure rotatably supported thereon and a luffable boom system arranged thereon, and a derrick boom, in which an auxiliary crane is used as derrick ballast. The auxiliary crane may be moved onto a ballast base plate attached to the derrick boom on the erection of the boom system, on which a very large counter-torque therefore may be applied, in order thus to form at least a large portion of the counter-weight.
The derrick ballast can thus be provided with ballast fast and simply. Instead of a complex stacking up of ballast plates to the height of the mass of the in-moving auxiliary crane, the auxiliary crane can drive onto the ballast base plate in a very simple and fast manner in order thus to form the corresponding derrick ballast. In this respect, the auxiliary crane also no longer has to be fastened to an adapter, which has to be provided accordingly, at the superstructure of the crane to be ballast loaded. This substantially simplifies the assembly and the dismantling and allows a substantially more flexible use of the auxiliary crane. This high derrick weight is thus frequently only required during the erection of the boom system since a particularly high counter-torque has to be applied here. After a corresponding erection of the boom system, the auxiliary crane can then again be traveled off the ballast base plate.
At least one counter-weight stack of counter-weight plates can additionally be stacked on the ballast base plate. The counter-weight plates can here be divided over different weight stacks to achieve a uniform distribution of the weight on the counter-weight plate.
At least one guying can be arranged between the derrick boom and the ballast base plate such that the stay poles are guided from the derrick boom, optionally with an interposition of length-variable cylinder arrangements, to a cross-brace, which together with lateral connection blocks, which serve for connecting the cross-brace to the ballast base plate, forms a kind of gate into which the auxiliary crane can drive.
The inclination of the ballast base plate can furthermore be detected via at least one inclination sensor, with the recorded inclination values being detected and monitored via a control the crane so that, if required, the inclination of the ballast base plate is returned into a desired range via the cylinder arrangement.
It can furthermore be determined via a sensor device whether the ballast base plate has been completely raised from the ground. This measured state value is advantageously likewise forwarded to the control (e.g., so that the control may prompt an operator of the crane via a display device or other means to add additional ballast if the ballast base plate has been completely raised from the ground).
The spacing between the ballast base plate and the superstructure of the crane can advantageously be determinable via a guide frame arranged between them to generate a comparatively larger ballast torque.
It is particularly advantageous that, after a corresponding erection of the boom system or after another crane operation in which a very large counter-ballast has to be provided, the ballast, which at least comprises the ballast base plate with the ballast located thereon, is decoupled from the crane via releasable connections, optionally via pin connections arranged between the cross-brace and the connection blocks, for the subsequent travel or rotation of the crane. After a corresponding decoupling of the ballast base plate with the ballast located thereon, the crane can be traveled or rotated without problem. This is therefore possible since the crane substantially no longer requires such a high counter-torque during the travel and rotation. The application of ballast by the central ballast is frequently sufficient for this state.
The method is advantageously further developed in that, after decoupling the ballast which is attached at the derrick boom and which at least comprises the ballast base plate with the ballast located thereon, if required, counter-stacking plates are received in a suspended manner at the cross-brace attached to the derrick boom or directly via corresponding connection apparatuses in order thus to form a constant ballast attached to the derrick boom. Such a constant ballast is sufficient to achieve the required payload, for example, for the assembly of the elements of plants, for example of wind power stations, when here in particular the maximum ballast load of the main crane with central ballast and superstructure ballast is not sufficient.
This constant ballast can advantageously be taken up via the connection means of the counter-weight plates, as required, directly from the decoupled ballast base plate of the ballast. In this alternative embodiment, there may no longer be any need for the attached cross-brace of the previously described embodiment variant.
Special payload tables are advantageously integrated in the crane control which can be selected for the case of the attached constant ballast, with this ensuring that the crane reliably actually does not tilt to the rear with an advantageously luffed boom system.
The method is particularly advantageously configured, in particular for the erection of the boom system, in that counter-weight plates are directly removed from the superstructure ballast and are stacked on the ballast base plate to increase the torque. The counter-weight plates are hereby therefore no longer active as superstructure ballast, but rather as derrick ballast and increase the torque without additional counter-weight plates here having to be transported in or away again later.
In one embodiment of the present disclosure, a crane may comprise a movable undercarriage, a superstructure rotatably supported thereon with a luffable boom system arranged thereon and a derrick boom and with a crane control. It is characterized in that it has a ballast apparatus as derrick ballast which at least comprises a ballast base plate for receiving an auxiliary crane, wherein they are connected via lateral connection blocks to a cross-brace such that a gate is formed into which the auxiliary crane can drive, with the cross-brace in turn being connected via stay poles to the derrick boom.
Respective length-variable elements in the form of hydraulic cylinder arrangements can advantageously be provided between the derrick boom and the cross-brace.
At least one counter-weight stack comprising counter-weight plates can additionally be stacked on the ballast base plate.
Releasable connections can advantageously be arranged between the cross-brace and the connection blocks. The total ballast base plate with the ballast located thereon can hereby be decoupled in a simple manner.
In accordance with a particular embodiment of the present disclosure, connection means can additionally be fastened to the cross-brace for the direct reception of counter-weight plates for forming a counter-weight arrangement attached to the derrick boom. These connection means can be mandrels such as those described in DE 20 2004 009 497 U1. Exactly just so many counter-weight plates are advantageously installed into the counter-weight arrangement that the crane reliably just does not tilt to the rear with a boom system which is luffed sufficiently for the travel position.
In accordance with another advantageous aspect of the present disclosure, placement feet are arranged at the cross-brace on which the cross-brace can be placed, in particular also during transport.
To increase the ballast, the auxiliary crane standing on the ballast base plate can additionally itself receive a ballast and can, if required, additionally still receive a load likewise acting as ballast at the crane hook.
Further features, details and advantages of the present disclosure will be explained in more detail with reference to embodiments shown in the figures.